A videoconferencing system may handle video from two sources at the same time. One example of a prior art system for handling video from two sources is the iPower system available from Polycom, Inc., the Assignee of the present disclosure. The iPower system allows user to include video of participants along with content in a videoconferencing meeting. In particular, the iPower system provides a dual images function. With the dual images function, the iPower system shares bandwidth between video of participants and video of content when content is selected to be shown. This allows conference participants to see other participants and visual content simultaneously.
In the iPower system, one video stream (e.g., video of participants) on one of the encoders is deemed more important than the other video stream (e.g., content). The iPower system receives feedback only from the one encoder associated with the video stream deemed more important. The feedback is in the form of differences between frames of the more important video stream. The iPower system has a table that describes what percentage of the bandwidth to allocate to the one encoder deemed more important. The feedback and total video rate are used to calculate an index that is used to retrieve a percentage value from the table. The bit rate for the one encoder deemed more important is then calculated as the total video rate multiplied by the percentage value retrieved from the table. The bit rate of the other encoder is set to the remainder of the bandwidth.
In a videoconference, however, a relatively fixed amount of bandwidth is typically available for video. When a new video stream is added or when multiple video streams are present, the prior art iPower system selects only one video source as important and statically divides the available bandwidth between the video sources. As a result, the video quality of one or both of the sources can suffer.
The subject matter of the present disclosure is directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above.